High-tension-telegraph-circuit protector.



R. C. COLE.

HIGH TENSION TELEGRAPH CIRCUIT PROTECTOR.

APPLICATION mznuov. 29. 1915.

1 ,1 99,349 Patented Sept. 26, 1916.

UNITED STATES PATENT OFFICE.

ROBERT C. COLE, 0F HARTFORD, CONNECTICUT, ASSIGNOR TO THE JOHNS-PRATT COMPANY, OF HARTFORD, CONNECTICUT, A CORPORATION OF CONNECTICUT.

I-IIGT-I-TENSION-TELEGRAPH-CIRCUIT PROTECTOR.

Specification of Letters Patent.

Patented Sept. 26, 1916.

Application filed November 29, 1915. Serial No. 63,963.

To all whom it may concern:

Be it known that I, ROBERT C. Conn, a citizen of the United States, residing at Hartford, .in the county of Hartford and State of Connecticut, have invented a new and useful Improvement in High-Tension- Telegraph-Circuit Protectors, of which the following is a specification.

This invention relates to a device which is designed to be used to protect the lines and instruments of telegraph, telephone and signal circuits of relatively low voltage from injury due to accidental crosses with high tension circuits.

The object of the invention is to provide an electrically eflicient and mechanically rugged device for this purpose which is made up of few parts that are cheap to manufacture, easy to assemble and that can be quickly replaced at any time by any one without danger.

The embodiment of the invention which is illustrated has a sheet metal base. On one end of this base is an insulating block of sufficient size to resist a current of a voltage of several times more than the normal voltage of the high tension current to be guarded against. On the other end of the base is an insulating block which only need be of such size as to resist a current of a Voltage of several times more than the normal voltage of the circuit to be protected. Mounted on the outer ends of these insulating blocks are conducting caps provided with means for the attachment of the ends of the circuit wires and with clips for the reception of the terminals of the inclosed fuse which is used to protect the low voltage circuit. Connected with the cap on the smaller insulator is a lightning arrester that has means for the attachment of a grounding wire.

Figure 1 of the accompanying drawings shows a plan of a protector which embodies this invention, with the fuse omitted. Fig. 2 shows a side elevation of the same with the inclosed fuse in place. Fig. 3 shows an end elevation of the complete protector. Fig. 4 is a diagrammatic View representing the manner of installing these protectors in the line which they are to protect.

The base 1 of the device which is illustrated is formed of sheet metal, preferably steel, stamped to shape with mortises in its ends. The insulators 2 and 3 are desirably formed of porcelain with grooves 4: in their sides of such width and depth that the insulators may be slipped into the mortises in the ends of the base. Screws 5 may be turned into the top of the base in such manner as to engage the sides of the insulators and hold them in place. The insulator 2 is desirably made of considerable height with a number of grooves 6 and flanges 7 for the purpose of providing the desired maximum dielectric strength and protection against surface leakage. The insulator 3 may be considerably lower than the insulator The upper ends of the insulators shown are grooved, and slipped on these upper ends, with their inturned edges extending into the grooves. are metallic caps 8. These caps are held in place by screws 9 and are provided with spring fingers 10 bent to form clips of the necessary shape to receive the terminals 11 of the inclosed fuse 12. These caps also have means 13 for the attachment of the ends of the circuit wires. Connected with the cap on the smaller insulator is a lightning arrester of common form consisting of conducting plates 1% and 15 with an interposed mica sheet 16. Connected with the outer conducting plate is a screw 17 on which is a binding nut 18 for the attachment of the end of a grounding wire. The metallic bases are fastened in position and the insulating blocks slipped into the ends. The caps are slipped upon the top of the insulators and the fuse is inserted into the fuse clipson the caps. One of these devices is placed on each side of the telegraph, tele phone or signal station it is to protect. The method of installing these protectors is dia' grammatically illustrated by Fig. 4, and for the purposes of explanation one system employing these protective devices is described, it being understood, however, that the figures represent an example only. Assuming that it is desired to protect the telegraph instruments located in stations S and connected in a circuit of 80 volts, from the effects of an accidental cross with a feeder F carrying current of 11,000 volts pressure to the motors M of an electric train on a track T, one of the protectors is located on each side of the stations, with the line wires L connected with the fuse slips on the top of the high insulators and the station wires WV connected with the fuse clips on the top of the low insulators. The lightning arresters A, of approximately 900 volts, would be grounded on the track, and fuses X of approximately amperes would be inserted in the fuse clips. Under these conditions, should a cross occur between the high tension feeder and the low tension telegraph circuit in any section between the stations, as at L, the high tension currents would flow through the fuses on each side of the section crossed and jump the lightning arresters A and pass to the ground. This would cause a dead short circuit and blow the fuses X at each end of the section that was crossed and thus save the instruments in the stations on each side of the crossed section from injury. Under the conditions referred to (merely as an example) the high insulators I in order to prevent a breakdown of the current carrying parts which they support, in case of a continued cross with thehigh tension Wiring, should be of sufficient size to resist a flash across them of several times the normalvoltage of the high tension line and such surges as would result, that is, these insulators would for safety be capable of resisting a flash across them of 55,000 volts, while the low insulators-would need to be only of such size as to resist a potential somewhat above that which would jump the lightning arr-esters. It has been den-ionstrated that with the conditions enumerated as an example under a cross the telegraph. instruments in the stations will be fully protected, in fact, at the instruments there was no indication whatever of abnormal trouble.

The invention claimed is;

1. A protective device consisting of abase, an insulator mounted on each end of the base, one insulator having greater dielectric strength and larger resistance to surface leakage than the other, conductors mounted on the outer ends of the insulators, said conductors having fuse receiving clips and means for the attachment of circuit Wires, and a lightning arrester mounted on the smaller insulator and connected electrically with the conductor on said insulator.

2. A protective device consisting of a metal base, an insulating block mounted on and slidably attached to each end of the base, conducting caps mounted upon the outer ends of the insulators, fuse clips and terminal attachments on said caps, and a lightning arrester mounted on one of the insulators and connected electrically with the cap at the outer end of said insulator.

3. A protective device consisting of a sheet metal base, an insulator mounted on and slidably attached to each end of the base, one insulator having greater dielectric strength and larger resistance to surface leakage than the other, metallic caps mounted on and slidably connected with the outer ends of the insulators, fuse clips and wire attachments projecting from the caps, and a lightning arrester mounted on the smaller insulator and electrically connected with the cap on said insulator.

4. A protective device consisting of a sheet metal base, an insulator mounted on and slidably attached to each end of the base, a metallic cap mounted on and slidably attached to the outer end of each insulator, and a fuse clip and a wire connector on each 'cap.

ROBERT C. COLE.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D.- 6; 

